I thought Crichton was clearly their best in the games and moments that mattered and Luai and a few others played well alongside him. Though admittedly didn't watch Samoa beat up on Greece and France.
The SF win was massive historically and an entertaining game but I don't recall being particularly impressed with either sides performance.
Samoa's historical record before the tournament was pretty irrelevant to what the players could achieved. Their entire side had NRL experience, over half had played in an NRL grand final (big game experience). Bouncing out in the quarters or semis would have been considered a disappointing result pretournament and it was only that first loss (after being the last squad in England and little training no warm up game leading in) that tempered expectations. Many forget they actually started favourites in that first game due to the talent in their squad.
Also don't think most tipped against them in either of those finals. From memory they were slight favourites against Tonga and slight outsiders against England.
Anyway, that's not to say Luai isn't a great player. His NRL record and some standout games in Origin and finals is testament to that. He was also one part of the talent that had Samoa expected to put on a good showing in the WC. I just think the "he led them there" thing and that achievement alone overplayed.
